It's good to see some attention paid to the subject, but it's not exactly a new revelation. Probably 15-20 years ago, my computer architecture professor commen

It's good to see some attention paid to the subject, but it's not exactly a new revelation. Probably 15-20 years ago, my computer architecture professor commented that, while CPUs of the past had relatively anemic number-crunching powers, all the pipelining and high clock speeds and other advancements in more recent CPUs had changed that, but corresponding advancements in memory bandwidth had not been made. Which in turn meant that the way you go about optimizing code needed to change. In the past it had been mostly about finding ways to eliminate instructions or simplify expressions, because the things that were holding you back were the ALU and the ability to plow through instructions. With all those things sped up massively but less improvement in RAM, it became very important to start thinking about memory access patterns and caches. We even had a homework assignment to optimize a matrix multiply, and the lesson learned was that the dominating factor wasn't what the code looks like the innermost loop, it was which direction you proceed through the matrices (row by row vs. column by column) because that determines memory access patterns.